Recent studies indicate substantial differences in drug use prevalence among adolescents of different ethnic backgrounds. However, because we still lack sufficient information about how these differences arise and how they affect adolescent well-being, such differences alone do not tell us whether or how to tailor prevention programs to specific minority groups . Developing more effective interventions for curbing substance use among the various ethnic/racial minority subgroups requires understanding the patterns of drug use and abuse in these populations, identifying the varying factors that put these adolescents at risk for or protect them from drug use and abuse, and assessing the impacts that such use has on their lives. This study seeks to provide that information by: 1. Characterizing the nature and extent of drug use and abuse over time across different racial and ethnic groups in a large and diverse sample of West Coast adolescents; 2. Identifying the risk and protective factors for drug use and abuse across these groups (Asian, Hispanic, Black, and White adolescents); 3. Assessing the effects of a) early drug use on dropping out of school; and b) chronic use during high school on subsequent behavioral and emotional problems (violence, school problems, drug dealing, poor mental health, and delinquency); and 4. Examining the comorbidity of drug use with other problem behaviors for different ethnic and racial groups at age 18. Among the hypotheses to be tested are: a) Black and Hispanic youth exhibit lower prevalence rates but higher rates of drug-related problems than White youth; b) Risk factors for problem use (all groups)include early involvement with drugs and a drug subculture, early deviance, poor family relationships,and poor mental health, while risk or protective factors that have greater impact for specific subgroups include religion (Blacks), education (Asians), and parental tolerance of use (Hispanics); and c) SES and neighborhood and school context are stronger predictors of multiple problem youth status than race/ethnicity. To carry out this agenda, we will analyze data from a longitudinal panel that includes information from over 4500 West Coast adolescents on drug and alcohol use, and related behaviors and attitudes. The sample, which was followed from grade 7 through grade 12, includes about 500 adolescents who had dropped out of school by their senior year and over 1300 minority youth. Hence it avoids the limitations of studies based solely on in- school students and homogeneous populations.